postgres_fdw: Disable batch insertion when there are WCO constraints.

When inserting a view referencing a foreign table that has WITH CHECK
OPTION constraints, in single-insert mode postgres_fdw retrieves the
data that was actually inserted on the remote side so that the WITH
CHECK OPTION constraints are enforced with the data locally, but in
batch-insert mode it cannot currently retrieve the data (except for the
row first inserted through the view), resulting in enforcing the WITH
CHECK OPTION constraints with the data passed from the core (except for
the first-inserted row), which led to incorrect results when inserting
into a view referencing a foreign table in which a remote BEFORE ROW
INSERT trigger changes the rows inserted through the view so that they
violate the view's WITH CHECK OPTION constraint.  Also, the query
inserting into the view caused an assertion failure in assert-enabled
builds.

Fix these by disabling batch insertion when inserting into such a view.

Back-patch to v14 where batch insertion was added.

Discussion: https://postgr.es/m/CAPmGK17LpbTZs4m4a_6THP54UBeK9fHvX8aVVA%2BC6yEZDZwQcg%40mail.gmail.com

diff --git a/contrib/postgres_fdw/expected/postgres_fdw.out b/contrib/postgres_fdw/expected/postgres_fdw.out
index 52d0c3f3ed25cd828b862b6678c8613e0eb3da4d..7bf35602b0245d6c5f70c739cf632a0db5c4d22b 100644 (file)
--- a/contrib/postgres_fdw/expected/postgres_fdw.out
+++ b/contrib/postgres_fdw/expected/postgres_fdw.out
@@ -6544,6 +6544,29 @@ SELECT * FROM foreign_tbl;
  20 | 30
 (1 row)
 
+-- We don't allow batch insert when there are any WCO constraints
+ALTER SERVER loopback OPTIONS (ADD batch_size '10');
+EXPLAIN (VERBOSE, COSTS OFF)
+INSERT INTO rw_view VALUES (0, 15), (0, 5);
+                                   QUERY PLAN                                   
+--------------------------------------------------------------------------------
+ Insert on public.foreign_tbl
+   Remote SQL: INSERT INTO public.base_tbl(a, b) VALUES ($1, $2) RETURNING a, b
+   Batch Size: 1
+   ->  Values Scan on "*VALUES*"
+         Output: "*VALUES*".column1, "*VALUES*".column2
+(5 rows)
+
+INSERT INTO rw_view VALUES (0, 15), (0, 5); -- should fail
+ERROR:  new row violates check option for view "rw_view"
+DETAIL:  Failing row contains (10, 5).
+SELECT * FROM foreign_tbl;
+ a  | b  
+----+----
+ 20 | 30
+(1 row)
+
+ALTER SERVER loopback OPTIONS (DROP batch_size);
 DROP FOREIGN TABLE foreign_tbl CASCADE;
 NOTICE:  drop cascades to view rw_view
 DROP TRIGGER row_before_insupd_trigger ON base_tbl;
@@ -6636,6 +6659,27 @@ SELECT * FROM foreign_tbl;
  20 | 30
 (1 row)
 
+-- We don't allow batch insert when there are any WCO constraints
+ALTER SERVER loopback OPTIONS (ADD batch_size '10');
+EXPLAIN (VERBOSE, COSTS OFF)
+INSERT INTO rw_view VALUES (0, 15), (0, 5);
+                       QUERY PLAN                       
+--------------------------------------------------------
+ Insert on public.parent_tbl
+   ->  Values Scan on "*VALUES*"
+         Output: "*VALUES*".column1, "*VALUES*".column2
+(3 rows)
+
+INSERT INTO rw_view VALUES (0, 15), (0, 5); -- should fail
+ERROR:  new row violates check option for view "rw_view"
+DETAIL:  Failing row contains (10, 5).
+SELECT * FROM foreign_tbl;
+ a  | b  
+----+----
+ 20 | 30
+(1 row)
+
+ALTER SERVER loopback OPTIONS (DROP batch_size);
 DROP FOREIGN TABLE foreign_tbl CASCADE;
 DROP TRIGGER row_before_insupd_trigger ON child_tbl;
 DROP TABLE parent_tbl CASCADE;

diff --git a/contrib/postgres_fdw/postgres_fdw.c b/contrib/postgres_fdw/postgres_fdw.c
index 048db542d34e8c8b12dccc8668d83cc8427b931e..16320170ceeaf320d289e62e3904e1e431a5c466 100644 (file)
--- a/contrib/postgres_fdw/postgres_fdw.c
+++ b/contrib/postgres_fdw/postgres_fdw.c
@@ -2043,8 +2043,9 @@ postgresGetForeignModifyBatchSize(ResultRelInfo *resultRelInfo)
        batch_size = get_batch_size_option(resultRelInfo->ri_RelationDesc);
 
    /*
-    * Disable batching when we have to use RETURNING or there are any
-    * BEFORE/AFTER ROW INSERT triggers on the foreign table.
+    * Disable batching when we have to use RETURNING, there are any
+    * BEFORE/AFTER ROW INSERT triggers on the foreign table, or there are any
+    * WITH CHECK OPTION constraints from parent views.
     *
     * When there are any BEFORE ROW INSERT triggers on the table, we can't
     * support it, because such triggers might query the table we're inserting
@@ -2052,6 +2053,7 @@ postgresGetForeignModifyBatchSize(ResultRelInfo *resultRelInfo)
     * and prepared for insertion are not there.
     */
    if (resultRelInfo->ri_projectReturning != NULL ||
+       resultRelInfo->ri_WithCheckOptions != NIL ||
        (resultRelInfo->ri_TrigDesc &&
         (resultRelInfo->ri_TrigDesc->trig_insert_before_row ||
          resultRelInfo->ri_TrigDesc->trig_insert_after_row)))

diff --git a/contrib/postgres_fdw/sql/postgres_fdw.sql b/contrib/postgres_fdw/sql/postgres_fdw.sql
index 2a250ee6324e019ff737ea4cf348be64a4ec980c..42735ae78a954d7b57485b0e0f34b9fea1a88c7e 100644 (file)
--- a/contrib/postgres_fdw/sql/postgres_fdw.sql
+++ b/contrib/postgres_fdw/sql/postgres_fdw.sql
@@ -1505,6 +1505,14 @@ UPDATE rw_view SET b = b + 15;
 UPDATE rw_view SET b = b + 15; -- ok
 SELECT * FROM foreign_tbl;
 
+-- We don't allow batch insert when there are any WCO constraints
+ALTER SERVER loopback OPTIONS (ADD batch_size '10');
+EXPLAIN (VERBOSE, COSTS OFF)
+INSERT INTO rw_view VALUES (0, 15), (0, 5);
+INSERT INTO rw_view VALUES (0, 15), (0, 5); -- should fail
+SELECT * FROM foreign_tbl;
+ALTER SERVER loopback OPTIONS (DROP batch_size);
+
 DROP FOREIGN TABLE foreign_tbl CASCADE;
 DROP TRIGGER row_before_insupd_trigger ON base_tbl;
 DROP TABLE base_tbl;
@@ -1543,6 +1551,14 @@ UPDATE rw_view SET b = b + 15;
 UPDATE rw_view SET b = b + 15; -- ok
 SELECT * FROM foreign_tbl;
 
+-- We don't allow batch insert when there are any WCO constraints
+ALTER SERVER loopback OPTIONS (ADD batch_size '10');
+EXPLAIN (VERBOSE, COSTS OFF)
+INSERT INTO rw_view VALUES (0, 15), (0, 5);
+INSERT INTO rw_view VALUES (0, 15), (0, 5); -- should fail
+SELECT * FROM foreign_tbl;
+ALTER SERVER loopback OPTIONS (DROP batch_size);
+
 DROP FOREIGN TABLE foreign_tbl CASCADE;
 DROP TRIGGER row_before_insupd_trigger ON child_tbl;
 DROP TABLE parent_tbl CASCADE;